Plastic compression of a collagen gel forms a much improved scaffold for ocular surface tissue engineering over conventional collagen gels

We compare the use of plastically compressed collagen gels to conventional collagen gels as scaffolds onto which corneal limbal epithelial cells (LECs) are seeded to construct an artificial corneal epithelium. LECs were isolated from bovine corneas (limbus) and seeded onto either conventional uncompressed or novel compressed collagen gels and grown in culture. Scanning electron microscopy (SEM) results showed that fibers within the uncompressed gel were loose and irregularly ordered, whereas the fibers within the compressed gel were densely packed and more evenly arranged. Quantitative analysis of LECs expansion across the surface of the two gels showed similar growth rates (p > 0.05). Under SEM, the LECs, expanded on uncompressed gels, showed a rough and heterogeneous morphology, whereas on the compressed gel, the cells displayed a smooth and homogeneous morphology. Transmission electron microscopy (TEM) results showed the compressed scaffold to contain collagen fibers of regular diameter and similar orientation resembling collagen fibers within the normal cornea. TEM and light microscopy also showed that cell–cell and cell–matrix attachment, stratification, and cell density were superior in LECs expanded upon compressed collagen gels. This study demonstrated that the compressed collagen gel was an excellent biomaterial scaffold highly suited to the construction of an artificial corneal epithelium and a significant improvement upon conventional collagen gels.

The plastic self organising map

A novel extension to Kohonen's self-organising map, called the plastic self organising map (PSOM), is presented. PSOM is unlike any other network because it only has one phase of operation. The PSOM does not go through a training cycle before testing, like the SOM does and its variants. Each pattern is thus treated identically for all time. The algorithm uses a graph structure to represent data and can add or remove neurons to learn dynamic nonstationary pattern sets. The network is tested on a real world radar application and an artificial nonstationary problem.

A simple device for multiplex ELISA made from melt-extruded plastic microcapillary film

We present a simple device for multiplex quantitative enzyme-linked immunosorbant assays (ELISA) made from a novel melt-extruded microcapillary film (MCF) containing a parallel array of 200µm capillaries along its length. To make ELISA devices different protein antigens or antibodies were immobilised inside individual microcapillaries within long reels of MCF extruded from fluorinated ethylene propylene (FEP). Short pieces of coated film were cut and interfaced with a pipette, allowing sequential uptake of samples and detection solutions into all capillaries from a reagent well. As well as being simple to produce, these FEP MCF devices have excellent light transmittance allowing direct optical interrogation of the capillaries for simple signal quantification. Proof of concept experiments demonstrate both quantitative and multiplex assays in FEP MCF devices using a standard direct ELISA procedure and read using a flatbed scanner. This new multiplex immunoassay platform should find applications ranging from lab detection to point-of-care and field diagnostics.

Identifying barriers and opportunities for transitions towards more sustainable agriculture through system analysis: the case of Vereda La Hoya, Colombia

The paper presents the results of studies which investigated farmers’ reasoning and behaviour with regards to the mis‐use of personal protective equipment and pesticide among smallholders in Colombia. First, the research approach is described. In particular, the structured mental models approach and the integrative agent‐centred framework are presented. These approaches permit to understand the farmers’ reasoning and behaviour in a system perspective. Second, the results are summarized. The methods adopted allowed not only for identifying the factors, but also the social dynamics influencing farmers. Finally, suggestions for interventions are provided, which are not limited to a technical fix, but address the underlying social causes of the problem.

Poverty, HIV, and barriers to education: street children's experiences in Tanzania

This article discusses the links between poverty, HIV/AIDS, and barriers to education, based on the first-hand experiences of ‘street children’ in northern Tanzania. Within the context of national levels of poverty, ‘cost-sharing’ in health and education sectors, and the AIDS epidemic, poor families in Tanzania are under considerable pressure, and increasing numbers of girls and boys are consequently seeking a living independently on the streets of towns and cities. My research with street children shows that some children orphaned by AIDS are subject to rejection and exploitation by the extended family after the death of their parent(s). They are exposed to considerable risks of abuse, sexual violence and HIV within the street environment. Here, I discuss the links between poverty, HIV and barriers to education, which compound young people’s vulnerability, and offer some policy recommendations in response to the young people’s experiences.

Exploring social barriers to adaptation: insights from Western Nepal

As the challenges and opportunities posed by climate change become increasingly apparent, the need for facilitating successful adaptation and enhancing adaptive capacity within the context of sustainable development is clear. With adaptation high on the agenda, the notion of limits and barriers to adaptation has recently received much attention within both academic and policymaking spheres. While emerging literature has been quick to depict limits and barriers in terms of natural, financial, or technologic processes, there is a clear shortfall in acknowledging social barriers to adaptation. It is against such a backdrop that this paper sets out to expose and explore some of the underlying features of social barriers to adaptation, drawing on insights from two case studies in the Western Nepal. This paper exposes the significant role of cognitive, normative and institutional factors in both influencing and prescribing adaptation. It explores how restrictive social environments can limit adaptation actions and influence adaptive capacity at the local level, particularly for the marginalised and socially excluded. The findings suggest a need for greater recognition of the diversity and complexity of social barriers, strategic planning and incorporation at national and local levels, as well as an emphasis on tackling the underlying drivers of vulnerability and social exclusion.

Determinants of healthy eating: a cross-national study on motives and barriers

The paper investigates the impact of motives and barriers to healthy eating on individuals' healthy eating intention and behaviour using a cross-national design. Data were collected from the UK and the Czech Republic via a self-completion questionnaire. Findings highlight the significance of intrinsic motives and psychological barriers in predicting both intention and healthy eating behaviour for both UK and Czech consumers, albeit their weight as well as the variance captured by these factors differs across the two national cultures. Findings also indicate that physical barriers are in fact unimportant when it comes to adopting a healthy eating diet. These findings are discussed in the light of previous research, while their implications for policy makers and researchers are highlighted.

A novel bogie design made of glass fibre reinforced plastic

This paper presents a completely new design of a bogie-frame made of glass fibre reinforced composites and its performance under various loading conditions predicted by finite element analysis. The bogie consists of two frames, with one placed on top of the other, and two axle ties connecting the axles. Each frame consists of two side arms and a transom between. The top frame is thinner and more compliant and has a higher curvature compared with the bottom frame. Variable vertical stiffness can be achieved before and after the contact between the two frames at the central section of the bogie to cope with different load levels. Finite element analysis played a very important role in the design of this structure. Stiffness and stress levels of the full scale bogie presented in this paper under various loading conditions have been predicted by using Marc provided by MSC Software. In order to verify the finite element analysis (FEA) models, a fifth scale prototype of the bogie has been made and tested under quasi-static loading conditions. Results of testing on the fifth scale bogie have been used to fine tune details like contact and friction in the fifth scale FEA models. These conditions were then applied to the full scale models. Finite element analysis results show that the stress levels in all directions are low compared with material strengths.

Understanding the barriers to real estate investment in developing economies

Baum (2008a) related the number of real estate funds investing in developing economies to simple economic and demographic variables, and showed that, while the popularity of markets was explained by population and GDP per capita, some countries receive more or less investment than the model predicted. Why is this? In this paper we undertake a literature review to identify the barriers which inhibit international real estate investment. We test our initial findings by questioning property investment professionals through semi-structured interviews. By doing this we were able to verify our list of barriers, identify those barriers which are most likely to affect real estate investors, and to indicate whether there are any real estate-specific variables that create barriers which have not received any academic attention. We show that distortions in international capital flows may be explained by a combination of these formal and informal barriers.

Using HIT to deliver integrated care for the frail elderly in the UK: current barriers and future challenges

In this paper we briefly describe the results of a 3 year project examining the use of Health Information Technologies (e.g., electronic patient record systems) to deliver integrated care. In particular, we focus on one group of patient (the frail elderly) and efforts to design an e-health supported healthcare pathway (the frail elderly pathway – FEP). The aim of FEP is to bring together clinicians and staff from health and social care and allow them to share patient information. Our findings show that progress in delivering a fully-supported and working FEP has been slow, not least because of the difficulties experienced by healthcare staff in using current IT systems. In addition, there are many strategic and technical issues which remain unresolved (e.g., systems interoperability).

UK innovation systems for new and renewable energy technologies: drivers, barriers and systems failures

A better understanding of the systemic processes by which innovation occurs is useful, both conceptually and to inform policymaking in support of innovation in more sustainable technologies. This paper analyses current innovation systems in the UK for a range of new and renewable energy technologies, and generates policy recommendations for improving the effectiveness of these innovation systems. Although incentives are in place in the UK to encourage innovation in these technologies, system failures—or ‘gaps’—are identified in moving technologies along the innovation chain, preventing their successful commercialisation. Sustained investment will be needed for these technologies to achieve their potential. It is argued that a stable and consistent policy framework is required to help create the conditions for this. In particular, such a framework should be aimed at improving risk/reward ratios for demonstration and pre-commercial stage technologies. This would enhance positive expectations, stimulate learning effects leading to cost reductions, and increase the likelihood of successful commercialisation.